Typically, a position sensor is mounted on a hydraulic cylinder for detecting a position of a piston during operation and for using a detection signal thereof as a control signal. Such a position sensor detects magnetism of a permanent magnet mounted in the piston and, normally, as illustrated in Patent Literature (PTL) 1, is mounted on a cylindrical cylinder tube by using a belt-shaped metal fitting band.
In the fitting band disclosed in PTL 1 described above, metal reinforcing plates (press plates) are, by a method such as spot welding, fixed to outer surfaces of reinforcing plate attaching portions formed at both ends of the fitting band so as to oppose each other, the position sensor is pinched between a pair of opposing reinforcing plates, and the pair of reinforcing plates are fastened with a fastening screw in the above state, such that the position sensor is fixed to an outer periphery of the cylinder tube.
However, in a case in which the position sensor is fixed on the outer periphery of the cylinder tube using such a fitting band, when the fastening screw is rotated and tightly fastened, due to frictional force acting between the fastening screw and the reinforcing plates, rotational force in a direction following the rotation of the fastening screw acts on the reinforcing plates. Accordingly, shearing force in the rotation direction of the fastening screw acts between the reinforcing plates and the reinforcing plate attaching portions of the fitting band, causing the welded portion between the reinforcing plates and the fitting band to become separated such that problems, such as a misalignment with respect to each other, easily occur.
Meanwhile, there is also a method of fixing the position sensor on the cylinder tube by, in a state in which the position sensor is directly pinched between the pair of reinforcing plate attaching portions without fixing the reinforcing plate attaching portions of the fitting band and the reinforcing plates to each other, abutting the reinforcing plates to the outer surface of the reinforcing plate attaching portions and, in that state, fastening the reinforcing plates from both sides with the fastening screw. Such a fixing method does not require the fitting band and the reinforcing plates to be fixed to each other with a method such as spot welding or the like; accordingly, while it has an advantage in that the fitting band is simple in structure, compared with a case in which the reinforcing plates and the reinforcing plate attaching portions are fixed to each other by spot welding or the like, it has a problem in that disposition in the rotation direction occur easily.